JP6700517B2 - Defoaming agent, water-soluble resin composition containing the same, and water-soluble resin aqueous solution - Google Patents

Description

  The present invention relates to an antifoaming agent, a water-soluble resin composition containing the same, and a water-soluble resin aqueous solution.

  "One or more antifoaming agents selected from fatty acid ester compounds, ether compounds, metal soap compounds or silicon compounds" are known (claim 2 of Patent Document 1).

JP-A-11-277877

When a conventional antifoaming agent is applied to a water-soluble resin, there is a problem that the transparency of the water-soluble resin is likely to be lowered. That is, when a conventional defoaming agent is applied to a sizing agent, an adhesive agent, a film or the like containing a water-soluble resin, there is a problem that the transparency of these is impaired.
An object of the present invention is to provide an antifoaming agent which is excellent in defoaming property and does not deteriorate transparency even when applied to a water-soluble resin.

Ｒ ^１ は炭素数１〜２５の活性水素化合物の反応残基、Ｒ ^２ 及びＲ ^３ は炭素数１〜２４のアシル基又はアロイル基、ＡＯは炭素数２〜１８のオキシアルキレン基、グリシドールの反応残基、炭素数４〜１８のアルキルグリシジルエーテルの反応残基又は炭素数５〜１８のアルケニルグリシジルエーテルの反応残基を表し、ｎは１〜１００の整数で一分子中に複数のｎが存在する場合、それぞれ同じでも異なっていてもよく、ｓは１〜１０の整数、ｐは０〜１０の整数、ｑは０〜９の整数、ｒは０〜９の整数、ｐ＋ｒは１〜１０の整数、ｐ＋ｑ＋ｒは１〜１０の整数である。 The feature of the defoaming agent of the present invention is a metal oxide fine particle selected from a polyether compound (A) having a cloud point of 20 to 60° C. in an aqueous 1% by weight ion exchange solution, and fumed metal oxide and colloidal metal oxide. Consisting of (B) ( without other ingredients) ,
The polyether compound (A) is at least one selected from the group consisting of the polyether compound (A1) represented by the general formula (1) and the polyether compound (A2) represented by the general formula (2). ,
Based on the weight of the polyether compound (A) and the metal oxide fine particles (B), the content of the polyether compound (A) is 80 to 99.9% by weight, and the content of the metal oxide fine particles (B) is The point is 0.1 to 20% by weight.

R ¹ is a reaction residue of an active hydrogen compound having 1 to 25 carbon atoms, R ² and R ³ are acyl groups or aroyl groups having 1 to 24 carbon atoms, AO is a reaction of an oxyalkylene group having 2 to 18 carbon atoms, and glycidol. A residue, a reaction residue of an alkyl glycidyl ether having 4 to 18 carbon atoms or a reaction residue of an alkenyl glycidyl ether having 5 to 18 carbon atoms, n is an integer of 1 to 100, and a plurality of n are present in one molecule. When it does, it may respectively be the same or different, s is an integer of 1-10, p is an integer of 0-10, q is an integer of 0-9, r is an integer of 0-9, and p+r is 1-10. An integer, p+q+r is an integer of 1-10.

Ｒ ^１ は炭素数１〜２５の活性水素化合物の反応残基、Ｒ ^２ 及びＲ ^３ は炭素数１〜２４のアシル基又はアロイル基、ＡＯは炭素数２〜１８のオキシアルキレン基、グリシドールの反応残基、炭素数４〜１８のアルキルグリシジルエーテルの反応残基又は炭素数５〜１８のアルケニルグリシジルエーテルの反応残基を表し、ｎは１〜１００の整数で一分子中に複数のｎが存在する場合、それぞれ同じでも異なっていてもよく、ｓは１〜１０の整数、ｐは０〜１０の整数、ｑは０〜９の整数、ｒは０〜９の整数、ｐ＋ｒは１〜１０の整数、ｐ＋ｑ＋ｒは１〜１０の整数である。 The feature of the defoaming agent of the present invention is that the metal compound fine particles selected from a polyether compound (A) having a cloud point of 20 to 60° C. in an aqueous 1 wt% ion-exchange solution and fumed metal oxides and colloidal metal oxides. Consisting of (B) and water (C) (no other ingredients included) ,
The polyether compound (A) is at least one selected from the group consisting of the polyether compound (A1) represented by the general formula (1) and the polyether compound (A2) represented by the general formula (2). ,
Based on the weight of the polyether compound (A) and the metal oxide fine particles (B), the content of the polyether compound (A) is 80 to 99.9% by weight, and the content of the metal oxide fine particles (B) is The gist is that the content of water is 0.1 to 20% by weight and the content of water (C) is 1 to 10% by weight.

R ¹ is a reaction residue of an active hydrogen compound having 1 to 25 carbon atoms, R ² and R ³ are acyl groups or aroyl groups having 1 to 24 carbon atoms, AO is an oxyalkylene group having 2 to 18 carbon atoms, and a reaction of glycidol A residue, a reaction residue of an alkyl glycidyl ether having 4 to 18 carbon atoms or a reaction residue of an alkenyl glycidyl ether having 5 to 18 carbon atoms, n is an integer of 1 to 100, and a plurality of n are present in one molecule. When it does, it may respectively be the same or different, s is an integer of 1-10, p is an integer of 0-10, q is an integer of 0-9, r is an integer of 0-9, and p+r is 1-10. An integer, p+q+r is an integer of 1-10.

  The feature of the water-soluble resin composition of the present invention is summarized in that it contains a water-soluble resin and the above defoaming agent.

  The feature of the water-soluble resin aqueous solution of the present invention is summarized in that it contains a water-soluble resin, the above defoaming agent, and water.

  The defoaming agent of the present invention does not deteriorate transparency even when applied to a water-soluble resin, and exhibits excellent defoaming property.

  Since the water-soluble resin composition of the present invention contains the above defoaming agent, it is excellent in defoaming property of an aqueous solution obtained by dissolving the water-soluble resin composition in water, and also excellent in transparency of the aqueous solution.

  Since the water-soluble resin aqueous solution of the present invention contains the above defoaming agent, it is excellent in transparency and defoaming property.

  As the polyether compound (A), a compound having a plurality of ether bonds in the molecule, which is liquid at 25° C., can be used, and a polyoxyalkylene compound can be preferably exemplified.

  The cloud point (° C.) of the polyether compound (A) in a 1 wt% ion exchange aqueous solution is preferably 20 to 60, more preferably 22 to 59, particularly preferably 24 to 58, and most preferably 25 to 57. .. Within this range, the defoaming property will be further improved, and the transparency will not be lowered even when applied to a water-soluble resin.

  The cloud point in a 1% by weight aqueous solution of ion exchange is one of the physical property values that is a measure of hydrophilicity. The higher the cloud point, the greater the hydrophilicity, and the value measured as follows. is there.

  Dissolve 99 g of ion-exchanged water and 1 g of sample uniformly (if not dissolved, cool until dissolved), take about 5 cc of this sample solution in a glass test tube, put a thermometer in the sample solution and raise the temperature while stirring. Then, the sample solution is made cloudy and then slowly cooled with stirring to read the temperature at which the sample solution becomes completely transparent, which is taken as the cloud point.

  The polyether compound (A) includes a polymer having an oxyalkylene group having 2 to 18 carbon atoms as a unit, and in the polyether compound (A1) represented by the general formula (1) and the general formula (2), Represented by the polyether compound (A2) represented by the formula (3), the polyether compound (A3) represented by the formula (3), the polyether compound (A4) represented by the formula (4) and the formula (5). At least one selected from the group consisting of polyether compounds (A5) can be preferably exemplified.

R ¹ is a reaction residue of an active hydrogen compound having 1 to 25 carbon atoms, R ² and R ³ are monovalent organic groups having 1 to 24 carbon atoms, R ⁴ is a divalent organic group having 1 to 24 carbon atoms, the reaction residue of R ⁵ is a hydroxyl group or a monovalent organic group having 1 to 24 carbon atoms, AO and OA is an oxyalkylene group having 2 to 18 carbon atoms, the reaction residue of glycidol, alkyl glycidyl ethers having 4 to 18 carbon atoms Or represents a reaction residue of an alkenyl glycidyl ether having 5 to 18 carbon atoms, n is an integer of 1 to 100, and when a plurality of n are present in one molecule, they may be the same or different, and s is 1 to Integer of 10, p is an integer of 0-10, q is an integer of 0-9, r is an integer of 0-9, m is an integer of 0-9, p+r is an integer of 1-10, p+q+r is 1-10. An integer, p+q+r+m is an integer of 2 to 10.

The reaction residue (R ¹ ) of an active hydrogen compound having 1 to 25 carbon atoms means a reaction residue obtained by removing active hydrogen from an active hydrogen compound having 1 to 25 carbon atoms.
The active hydrogen-containing compound having 1 to 25 carbon atoms, a hydroxyl group (-OH), an imino group (-NH-), a compound containing at least one an amino group (-NH ₂₎ and / or carboxyl group (-COOH) is Included, including alcohols, amides, amines, carboxylic acids, hydroxycarboxylic acids and aminocarboxylic acids.

  As the alcohol, monool (methanol, butanol, stearyl alcohol, oleyl alcohol and isostearyl alcohol, etc.) and polyol (ethylene glycol, propylene glycol, glycerin, diglycerin, tetraglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, Dihydroxyacetone, fructose, glucose, mannose, galactose, sucrose, lactose, trehalose, etc.) and the like.

  Examples of the amide include monoamide (formic acid amide, propionic acid amide, stearyl amide, etc.) and polyamide (malonic acid diamide, ethylene bisoctyl amide, etc.).

  Examples of amines include monoamines (dimethylamine, ethylamine, aniline, stearylamine, etc.), polyamines (ethylenediamine, diethylenetriamine, triethylenetetramine, etc.), and the like.

  Examples of the carboxylic acid include monocarboxylic acids (acetic acid, stearic acid, oleic acid, benzoic acid, etc.) and polycarboxylic acids (maleic acid, hexanedioic acid, etc.) and the like.

  Examples of the hydroxycarboxylic acid include hydroxyacetic acid, tartaric acid, malic acid and 12-hydroxystearic acid.

  Examples of the aminocarboxylic acid include glycine, 4-aminobutyric acid, 6-aminohexanoic acid and 12-aminolauric acid.

Monovalent organic group having 1 to 24 carbon atoms as the ^(R 2, R ^3), an alkyl group (R), an alkenyl group (R '), an acyl group (-COR), a aroyl group (-COR'), N -Alkylcarbamoyl group (-CONHR), N-alkenylcarbamoyl group (-CONHR'), alkylcarbonylamino group (-NHCOR), alkenylcarbonylamino group (-NHCOR'), alkylcarboxyamino group (alkylcarbamate group, -NHCOOR) ) And an alkenylcarboxyamino group (alkenyl carbamate group, —NHCOOR′).

  Examples of the alkyl group (R) include methyl, ethyl, isopropyl, t-butyl, octyl, 2-ethylhexyl, dodecyl and octadecyl.

  Examples of the alkenyl group (R') include vinyl, propenyl, hexenyl, isooctenyl, dodecenyl and octadecenyl.

Among the hydroxyl group or the monovalent organic group having 1 to 24 carbon atoms (R ⁵ ), the monovalent organic group having 1 to 24 carbon atoms includes the same organic groups as described above.

Examples of the divalent organic group having 1 to 24 carbon atoms ^{(R 4),} an alkylene group (T), an alkenylene group (T '), 1- oxaalkylene group (-OT -), 1- oxa alkenylene group (-OT '-), 1-oxoalkylene group (-COT-), 1-oxoalkenylene group (-COT'-), 1-aza-2-oxoalkylene group (-NHCOT-), 1-aza-2-oxoalkenylene Group (-NHCOT'-), 1-oxo-2-azaalkylene group (-CONHT-), 1-oxo-2-azaalkenylene group (-CONHT'-), 1-aza-2-oxo-3-oxa An alkylene group (-NHCOOT-) and a 1-aza-2-oxo-3-oxaalkenylene group (-NHCOOT'-) are included.

  Examples of the alkylene group (T) include methylene, ethylene, isobutylene, 1,10-decylene, 1,2-decylene, 1,12-dodecylene, 1,2-dodecylene and 1,2-octadecylene.

  Examples of the alkenylene group (T') include ethynylene, isobutynylene, 1,10-decynylene, 1-octylethynylene, 1-octenylethylene, 1,12-dodecynylene and 1-octadecenylethylene.

  Of the oxyalkylene group having 2 to 18 carbon atoms, the reaction residue of glycidol, the reaction residue of the alkyl glycidyl ether having 4 to 18 carbon atoms or the reaction residue of the alkenyl glycidyl ether having 5 to 18 carbon atoms (AO, OA) As the oxyalkylene group having 2 to 18 carbon atoms, oxyethylene, oxypropylene, oxybutylene, oxyisobutylene, oxy-1,2-decylene, oxy-1,12-dodecylene, oxy-1,2-dodecylene and oxy- 1,2-octadecylene and the like can be mentioned.

  Further, among (AO, OA), examples of the alkyl glycidyl ether having 4 to 18 carbon atoms include methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether and octadecyl glycidyl ether. Be done.

  Further, among (AO, OA), the alkenyl glycidyl ether having 5 to 18 carbon atoms includes vinyl glycidyl ether, butenyl glycidyl ether, 2-ethylhexenyl glycidyl ether, dodecenyl glycidyl ether and octadecenyl glycidyl. Examples include ether and the like.

  n is an integer of 1 to 100, preferably an integer of 10 to 90, and more preferably an integer of 15 to 80.

  Examples of the polyether compound (A1) represented by the general formula (1) include polyoxyethylene polyoxypropylene monobutyl ether, ethylene oxide propylene oxide block adduct of dodecyl alcohol, propylene oxide ethylene oxide block adduct of tetradecyl alcohol, 2- Ethylenehexyl alcohol ethylene oxide propylene oxide block adduct, trimethylol propane propylene oxide ethylene oxide block adduct, polyoxyethylene polyoxypropylene glycol (block addition), glycerin ethylene oxide propylene oxide block adduct, glycerin propylene oxide ethylene oxide block adduct , An ethylene oxide propylene oxide block adduct of monododecylamine, and an ethylene oxide propylene oxide block adduct of pentaerythritol.

  Examples of the polyether compound (A2) represented by the general formula (2) include polyoxyethylene polyoxypropylene glycol (block addition) dioleate, glycerin ethylene oxide propylene oxide block adduct monostearate, and maleic acid ethylene oxide propylene. Examples include oxide block adducts such as monomethyl ether.

  Examples of the polyether compound (A3) represented by the general formula (3) include ethylene oxide adducts of ethylenebisstearylamide, and esterified products of trimellitic acid with polyoxyethylene polyoxypropylene monobutyl ether and 2-ethylhexanol. Can be mentioned.

  Examples of the polyether compound (A4) represented by the general formula (4) include monooleate of ethylene oxide adduct of castor oil and ethylene oxide adduct of glycerin bis(12-hydroxystearate).

  Examples of the polyether compound (A5) represented by the general formula (5) include a reaction product of polyoxyethylene monolauryl ether, polyoxyethylene glycol, and hexamethylene diisocyanate.

  Among these, the polyether compound (A1) represented by the general formula (1) and the polyether compound (A2) represented by the general formula (2) are preferable from the viewpoint of defoaming property and the like.

  Examples of the metal oxide fine particles (B) selected from fumed metal oxides and colloidal metal oxides include hydrophilic fumed metal oxides, hydrophobic fumed metal oxides, hydrophilic colloidal metal oxides and hydrophobic colloidal metal oxides. Hydrophilic fumed silica, hydrophobic fumed silica, hydrophobic fumed alumina, hydrophobic fumed titanium, hydrophilic colloidal silica and hydrophobic colloidal silica can be used. Of these, fumed metal oxides are preferable, hydrophobic fumed metal oxides are more preferable, and hydrophobic fumed silica is particularly preferable, from the viewpoints of defoaming property and cost.

  The metal oxide fine particles (B) can be easily obtained from the market. The trade names of the hydrophobic fumed silica are the AEROSIL series (R972, R974, RX200, RX300, RY200, R202 and R805, Nippon Aerosil Co., Ltd., and “AEROSIL” is a registered trademark of Evonik Degussa GmbH. REOLOSIL series (MT-10, DM-10 and DM-20S, etc., Tokuyama Corporation, "REOLOSIL" are registered trademarks of the same company, the same applies hereinafter); HDK series (HDKH15 and HDKH18) Asahi Kasei Wacker Silicone Co., Ltd., “HDK” is a registered trademark of Wacker Chemie AG. The same applies hereinafter); and CAB-O-SIL series (TS-720, TS-622, TS-382, etc., "CAB-O-SIL", a product of Cabot Carbon Co., Ltd., is a registered trademark of KYABOTCO-PARAYSIAN, and the same shall apply hereinafter).

  The trade name of hydrophilic fumed silica is AEROSIL series (50, 130, 200, 300 and R812 etc.); REOLOSIL series (QS-10, QS-30, QS-40 and S-102 etc., Tokuyama Corporation) HDK series (HDKN20, HDKS13, etc., Asahi Kasei Wacker Silicone Co., Ltd.) CAB-O-SIL series (EH-5, S-5, etc., Cabot Carbon Co., Ltd.) and the like.

  Examples of the trade name of the hydrophobic fumed alumina include AEROXIDE series (AluC805 and the like, Nippon Aerosil Co., Ltd., “AEROXIDE” is a registered trademark of Evonik Degussa GM Behr. The same applies hereinafter).

  Trade names of hydrophobic fumed titanium include AEROXIDE series (T805 and NKT90, etc.).

  The trade names of the hydrophilic colloidal silica are Snowtex series (S, NS, etc., Nissan Chemical Industries, Ltd., "Snowtex" is a registered trademark of the company), Adeleite series (AT-20A, etc.) ADEKA and "Adelight" are registered trademarks of the same company.) and the like.

  CAB-O-SIL TGC191 etc. are mentioned as a brand name of hydrophobic colloidal silica.

  The methanol wettability (M value) of the metal oxide fine particles (B) is preferably 35 to 65, more preferably 36 to 63, particularly preferably 38 to 62, and most preferably 40 to 60. Within this range, the defoaming property will be further improved.

  The M value is an index showing the degree of hydrophobicity, and means the volume% of the homogeneous dispersion having the lowest methanol concentration among several water/methanol mixed solutions having different concentrations, and is measured as follows. Is the value to be set. It can be said that the higher this value, the higher the hydrophobicity.

<Methanol wettability (M value) measurement method>
A water/methanol mixed solution in which the concentration of methanol was changed at intervals of 5% by volume was prepared, and 5 ml of this was put into a test tube having a volume of 10 ml. Then, 0.2 g of the measurement sample was put, the test tube was covered, and the test tube was turned upside down 20 times and allowed to stand for 1 to 2 minutes. After that, the aggregate was observed. Of the dispersion liquids that have been wet and uniformly dispersed, the concentration (volume%) of methanol in the dispersion liquid having the smallest methanol concentration is taken as the M value {it is customary not to describe the unit of the M value (volume%). }.

  The content (% by weight) of the polyether compound (A) is preferably 80 to 99.9, more preferably 85 to 99, based on the weight of the polyether compound (A) and the metal oxide fine particles (B). .8, particularly preferably 88 to 99.7, and most preferably 90 to 99.5. Within these ranges, the defoaming property and handleability will be further improved.

  The content (% by weight) of the metal oxide fine particles (B) is preferably 0.1 to 20 based on the weight of the polyether compound (A) and the metal oxide fine particles (B), more preferably 0. 2 to 15, particularly preferably 0.3 to 12, and most preferably 0.5 to 10. Within these ranges, the defoaming property and handleability will be further improved.

  The defoaming agent of the present invention is composed of polyether (A) and metal oxide fine particles (B), that is, contains no other component, but the defoaming agent of the present invention further contains water (C). You can The inclusion of water has the effect of reducing the risk of ignition and increasing the handling safety. It also has the effect of improving the low temperature fluidity of the defoamer. As water, distilled water, ion-exchanged water, tap water, industrial water, well water, spring water, river water, etc. can be used. Of these, tap water, industrial water, ion-exchanged water and distilled water are preferable, and ion-exchanged water and distilled water are more preferable.

  When water (C) is contained, the content (% by weight) of water (C) is preferably 1 to 10 based on the weight of the polyether compound (A) and the metal oxide fine particles (B), and It is preferably 2 to 8, and particularly preferably 3 to 6.

  The defoaming agent of the present invention exerts excellent defoaming property against an aqueous solution of a water-soluble resin (particularly polyvinyl alcohol) and does not reduce transparency, but an aqueous foaming liquid other than the aqueous solution of the water-soluble resin {for example, drainage. , Papermaking process white water, water-based paint, etc.} are also effective.

  When the antifoaming agent of the present invention is added to the water-soluble resin, it may be added at any timing, but it is preferable that the antifoaming agent is uniformly mixed after the addition. In addition, at the time of addition, the antifoaming agent may be diluted with an appropriate diluent solvent (for example, methanol or water) (the diluent solvent is preferably distilled off during or after mixing).

  When the antifoaming agent of the present invention is added to the water-soluble resin aqueous solution, it may be added at any timing, and the antifoaming agent may be diluted with a suitable diluent solvent (for example, methanol or water) at the time of addition. Good.

  The water-soluble resin composition of the present invention contains a water-soluble resin and the above defoaming agent, and as the water-soluble resin, an alkyd resin, an acrylic resin, a styrene-maleic acid copolymer, a cellulose derivative (methyl cellulose, carboxymethyl cellulose, Hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose etc.), polyvinylpyrrolidone, polyvinyl alcohol, starch, starch derivatives (oxidized starch and cationized starch etc.), polyacrylamide, polyethylene glycol and polysaccharides (xanthan gum and guar gum etc.) . Of these, polyvinyl alcohol is preferred.

  Although the content of the defoaming agent can be appropriately determined according to the foaming state, the content of the defoaming agent contained in the water-soluble resin composition is about 0.01 to 1% by weight based on the weight of the water-soluble resin. Is.

  The water-soluble resin aqueous solution of the present invention contains a water-soluble resin, the above defoaming agent, and water. As the water-soluble resin and water, the same ones as described above can be used.

  The content of the defoaming agent can be appropriately determined according to the foaming state, but the content of the defoaming agent contained in the water-soluble resin aqueous solution is about 0.01 to 1% by weight based on the weight of the water-soluble resin. is there.

  The content of water can be appropriately determined depending on the application etc., but the content of water contained in the water-soluble resin aqueous solution is about 300 to 10000 wt% based on the weight of the water-soluble resin.

  Hereinafter, "parts" means "parts by weight", "%" means "% by weight", and "cloud point" means "% cloud point in 1% by weight aqueous solution of ion exchange" unless otherwise specified.

The following polyether compounds (a1) to (a5) were used as the polyether compound (A).
Polyether compound (a1): Propylene oxide (40 mol) ethylene oxide (15 mol) block adduct of glycerin, cloud point 31° C.
Polyether compound (a2): ethylene oxide (8 mol) propylene oxide (7 mol) block adduct of 2-ethylhexanol, cloud point 20° C.
Polyether compound (a3): Diolate of ethylene oxide (13 mol) propylene oxide (30 mol) block copolymer, cloud point 25° C.
Polyether compound (a4): butanol ethylene oxide (45 mol) propylene oxide (35 mol) block adduct, cloud point 57° C.
Polyether compound (a5): ethylene oxide (22 mol) propylene oxide (19 mol) block adduct of lauryl alcohol, cloud point 28° C.

The following fumed silica (b1) to (b4) obtained from Nippon Aerosil Co., Ltd. were used as the metal oxide fine particles (B).
Fumed silica (b1): AEROSIL R974, M value 40
Fumed silica (b2): AEROSIL R972, M value 45
Fumed silica (b3): AEROSIL R805, M value 50
Fumed silica (b4): AEROSIL RX300, M value 60

<Example 1>
In a stirrable container, 990 parts of the polyether compound (a1) and 10 parts of the fumed silica (b1) were stirred and mixed for 30 minutes to obtain an antifoaming agent (1) of the present invention.

<Example 2>
In a stirrable container, 995 parts of the polyether compound (a2) and 5 parts of the fumed silica (b2) were stirred and mixed for 30 minutes to obtain an antifoaming agent (2) of the present invention.

<Example 3>
In a container capable of stirring, 900 parts of the polyether compound (a3) and 100 parts of fumed silica (b3) were stirred and mixed for 30 minutes to obtain an antifoaming agent (3) of the present invention.

<Example 4>
In a container capable of stirring, 970 parts of the polyether compound (a4), 30 parts of fumed silica (b1) and 60 parts of water (c1) {ion-exchanged water} are stirred and mixed for 30 minutes to defoam the present invention. The agent (4) was obtained.

<Example 5>
In a stirrable container, 950 parts of the polyether compound (a5), 50 parts of fumed silica (b4) and 30 parts of water (c1) were stirred and mixed for 30 minutes to give the antifoaming agent (5) of the present invention. Obtained.

<Example 6>
In a container capable of stirring, 500 parts of the polyether compound (a2), 470 parts of the polyether compound (a5), 30 parts of the fumed silica (b1) and 60 parts of water (c1) were stirred and mixed for 30 minutes to obtain a mixture. An antifoaming agent (6) of the invention was obtained.

<Example 7>
In a container capable of stirring, 300 parts of the polyether compound (a1), 697 parts of the polyether compound (a5), 3 parts of fumed silica (b2) and 100 parts of water (c1) were stirred and mixed for 30 minutes to prepare a mixture. An antifoaming agent (7) of the invention was obtained.

<Example 8>
In a container capable of stirring, 300 parts of the polyether compound (a3), 600 parts of the polyether compound (a5), 100 parts of fumed silica (b3) and 30 parts of water (c1) are stirred and mixed for 30 minutes to prepare a mixture. An antifoaming agent (8) of the invention was obtained.

<Example 9>
In a container capable of stirring, 300 parts of the polyether compound (a4), 695 parts of the polyether compound (a5), 5 parts of the fumed silica (b4) and 30 parts of water (c1) were stirred and mixed for 30 minutes to prepare a mixture. An antifoaming agent (9) of the invention was obtained.

<Comparative Example 1>
The metal soap-based defoaming agent "Nopco DF122-NS"("DF-5" used in the examples of Patent Document 1) was used as a comparative defoaming agent (H1).

  Using the defoaming agents (1) to (9) and (H1), the defoaming property and the transparency were evaluated as follows, and the evaluation results are shown in Tables 1 and 2.

<Evaluation of defoaming property>
1. Preparation of water-soluble resin composition for test Polyvinyl alcohol [Kuraray Poval PVA-217 (polymerization degree 1,700, saponification degree 88 mol%), Kuraray Co., Ltd.] 100 parts and evaluation sample (each antifoaming agent) 0.5 part The mixture was uniformly mixed to obtain a test water-soluble resin composition.

2. Preparation of Defoaming Test Liquid 40 parts of the test water-soluble resin composition and 960 parts of ion-exchanged water (about 25° C.) were heated to 90° C. with stirring and mixing, and the stirring and mixing was continued at 90° C. for 30 minutes to continue the test water-soluble resin After the composition was uniformly dissolved, it was cooled to about 25° C., and ion-exchanged water evaporated by heating was added to adjust the polyvinyl alcohol concentration to 4% to obtain a defoaming test liquid.
A defoaming test liquid (blank) was also prepared in the same manner as above except that the test water-soluble resin composition was changed to polyvinyl alcohol (one in which the defoaming agent was not uniformly mixed).

3. Defoaming Test A glass 500 ml graduated cylinder (hereinafter referred to as a foam tube) was erected in a water bath whose temperature was adjusted to 80° C. to the scale of 95 ml of the foam tube, and the foam tube was cooled to 80° C. Put 100 ml of the temperature controlled defoaming test liquid into the bottom of the foam tube, and bubble nitrogen gas at 300 ml/min to bubble the defoaming test liquid at 300 ml/min while changing the volume of foam and foaming liquid. Readings were made 15 seconds after the start of the test, 1 minute later, and 2 minutes later. The smaller the number, the higher the defoaming property, which is preferable.

表中、「−」はメスシリンダーで測定可能な５００ｍｌを超えており、測定不能であったことを示す。

In the table, "-" indicates that measurement was impossible because it exceeded 500 ml which was measurable with a graduated cylinder.

  The defoaming agent of the present invention exhibited excellent defoaming properties as compared with the comparative defoaming agent.

<Evaluation of transparency>
After the test, the defoaming test liquid used in the defoaming test is left to stand for 24 hours at 25° C. in a sealed state to be defoamed to obtain a transparency test liquid. The haze value (%:% by weight) of this transparency test liquid Rather, it is the percentage of the scattered light with respect to the total transmitted light. The lower the haze value, the better the transparency.

  When the defoaming agent of the present invention was used, the transparency was not adversely affected as in the case where the defoaming agent was not mixed. The antifoaming agent (H1) used in Patent Document 1 had a significant adverse effect on transparency.

  The defoaming agent of the present invention is suitable for a step of using a water-soluble resin in the fields of chemical industry, petroleum industry, textile industry, paper pulp industry, etc. where a water-soluble resin is used.

Claims (8)

It comprises a polyether compound (A) having a cloud point of 20 to 60° C. in a 1% by weight ion exchange aqueous solution and metal oxide fine particles (B) selected from fumed metal oxides and colloidal metal oxides (other components Not included) ,
The polyether compound (A) is at least one selected from the group consisting of the polyether compound (A1) represented by the general formula (1) and the polyether compound (A2) represented by the general formula (2). ,
Based on the weight of the polyether compound (A) and the metal oxide fine particles (B), the content of the polyether compound (A) is 80 to 99.9% by weight, and the content of the metal oxide fine particles (B) is Defoaming agent, characterized in that it is 0.1 to 20% by weight.

R ¹ is a reaction residue of an active hydrogen compound having 1 to 25 carbon atoms, R ² and R ³ are acyl groups or aroyl groups having 1 to 24 carbon atoms, AO is an oxyalkylene group having 2 to 18 carbon atoms, and a reaction of glycidol A residue, a reaction residue of an alkyl glycidyl ether having 4 to 18 carbon atoms or a reaction residue of an alkenyl glycidyl ether having 5 to 18 carbon atoms, n is an integer of 1 to 100, and a plurality of n are present in one molecule. When it does, it may respectively be the same or different, s is an integer of 1-10, p is an integer of 0-10, q is an integer of 0-9, r is an integer of 0-9, and p+r is 1-10. An integer, p+q+r is an integer of 1-10. From a polyether compound (A) having a cloud point of 20 to 60° C. in a 1% by weight ion exchange aqueous solution, metal oxide fine particles (B) selected from fumed metal oxides and colloidal metal oxides, and water (C) Nari (without other ingredients) ,
The polyether compound (A) is at least one selected from the group consisting of the polyether compound (A1) represented by the general formula (1) and the polyether compound (A2) represented by the general formula (2). ,
Based on the weight of the polyether compound (A) and the metal oxide fine particles (B), the content of the polyether compound (A) is 80 to 99.9% by weight, and the content of the metal oxide fine particles (B) is An antifoaming agent, characterized in that the content of water is 0.1 to 20% by weight and the content of water (C) is 1 to 10% by weight.

R ¹ is a reaction residue of an active hydrogen compound having 1 to 25 carbon atoms, R ² and R ³ are acyl groups or aroyl groups having 1 to 24 carbon atoms, AO is an oxyalkylene group having 2 to 18 carbon atoms, and a reaction of glycidol A residue, a reaction residue of an alkyl glycidyl ether having 4 to 18 carbon atoms or a reaction residue of an alkenyl glycidyl ether having 5 to 18 carbon atoms, n is an integer of 1 to 100, and a plurality of n are present in one molecule. When it does, it may respectively be the same or different, s is an integer of 1-10, p is an integer of 0-10, q is an integer of 0-9, r is an integer of 0-9, and p+r is 1-10. An integer, p+q+r is an integer of 1-10. The antifoaming agent according to claim 1 or 2, wherein the metal oxide fine particles (B) have a methanol wettability (M value) of 35 to 65. The defoaming agent according to any one of claims 1 to 3, wherein the metal oxide fine particles (B) are fumed silica. Water-soluble resin composition which comprises a defoaming agent according to any one of the water-soluble resin according to claim 1-4. Water-soluble resin aqueous solution comprising a water-soluble resin, a defoaming agent and water according to any one of claims 1-4. The water-soluble resin composition according to claim 5 , wherein the water-soluble resin is polyvinyl alcohol. The water-soluble resin aqueous solution according to claim 6 , wherein the water-soluble resin is polyvinyl alcohol.